#include<iostream>
using namespace std;
const int MAX_LENGTH = 201;
int main(){
	int n;
	cin >> n;
	int map[MAX_LENGTH][MAX_LENGTH];
	int dis[MAX_LENGTH];
	for (int i = 0; i < n; i++){
		for (int j = i+1; j < n; j++){
			cin >> map[i][j];
			map[j][i] = map[i][j];
		}
	}
	for (int i = 1; i < n; i++){
		dis[i] = map[0][i];
	}
	for (int i = 1; i < n; i++){
		for (int j = 1; j < n; j++){
			if (j == i) continue;
			if (dis[j] > dis[i]+map[i][j]) dis[j] = dis[i]+map[i][j];
		}
	}
	cout << dis[n-1] << endl;
	return 0;
} 
